I have a Graflex Series B with a serial number of 6133. Could anyone tell the approximate year of Mfg and value? Also- can you provide sites that provides this type of information (or book references)? Thanks!

This in NOT a valid Graflex serial number. Serial number should be at least 5 (five) digits and on a Series B it will be a 6 (six) digit number as 5 digit numbers were used up 10 to 15 years or more before the Series B came into existance.
Graflex SLR serial numbers are either stamped into the lip of the view hood opening (early models) or behind the top of the view hood on the inside of the view hood door and may require disconnecting the top of the view hood to see (later models).
http://www.graflex.org/helpboard/viewtopic.php?topic=3631&forum=23&3 one of the first RB Series B.